Blank stacking, straightening and delivery means

ABSTRACT

Apparatus for stacking and straightening folded tubular boxes is constructed with a front barrier, which arrests forward box movement, having offset upper and lower vertical portions with the lower portion having a downward and rearwardly inclined section at the bottom thereof. A longitudinally oscillating slapper bar for engaging the rear of the stack is positioned opposite the vertical sections of the barrier and is disposed above the incline in the barrier. The inclined portion of the front barrier serves to prevent excessive buildup of weight in the stack from impeding the entry of boxes being fed to the bottom of the stack. Lift screws prevent excessive buildup of weight at the rear of the stack while oscillating roller means engaging the stack from below prevent excessive buildup of weight at the front of the stack. A roller device movable with the front barrier supports the continuous belt means which delivers folded boxes to the stacking section and supports the upper flight of this belt means in the critical area adjacent the front barrier. Additional roller means are selectively positionable to support additional portions of the delivery belt as required. Mounting for the roller means is such that they are automatically moved to retracted positions as the barrier means moves past in adjusting the apparatus for operation on shorter boxes. A slat hinged at one end thereof and supporting a roller acts to exert a downward force on the stack of boxes in the stacker with the roller being positioned toward the rear of the stack to prevent the portion of the stack engaged by lift screws from rising faster than the leading edge of the stack and thereby tipping the leading edge downward to impede takeoff. Another member also exerts a downward force on the stack primarily at the rear thereof. This member is maintained in a horizontal position by means of parallel linkages in an effort to maintain the folded boxes in the stack in horizontal position.

United States Patent [72] Inventor Albert F. Shields Forest Hills, NY.

[2 I Appl. No. 779,459

[22] Filed Nov. 27, 1968 [4S] Patented Aug. 24, 1971 [73] Assignee S 8: S Corrugated Paper Machinery Co.,

Inc. Brooklyn, N.Y.

[54] BLANK STACKING, STRAIGHTENING AND DELIVERY MEANS 7 Claims, 8 Drawing Figs.

52 us. Cl 214/6 BA, 271/75, 271/86 [51] Int. Cl 365g 57/30 [50] Field of Search 214/62;

Primary Examiner-Gerald M. Forlenza Assistant Examiner-Robert J Spar Attorney-Ostrolenk, Faber, Gerb & Soffen ABSTRACT: Apparatus for stacking and straightening folded tubular boxes is constructed with a front barrier, which arrests forward box movement, having offset upper and lower vertical portions with the lower portion having a downward and rearwardly inclined section at the bottom thereof. A longitudinally oscillating slapper bar for engaging the rear of the stack is positioned opposite the vertical sections of the barrier and is disposed above the incline in the barrier. The inclined portion of the front barrier serves to prevent excessive buildup of weight in the stack from impeding the entry of boxes being fed to the bottom of the stack. Lift screws prevent excessive buildup of weight at the rear of the stack while oscillating roller means engaging the stack from below prevent excessive buildup of weight at the front of the stack.

4 A roller device movable with the front barrier supports the continuous belt means which delivers folded boxes to the stacking section and supports the upper flight of this belt means in the critical area adjacent the front barrier. Additional roller means are selectively positionable to support additional portions of the delivery belt as required. Mounting for the roller means is such that they are automatically moved to retracted positions as the barrier means moves past in adjusting the apparatus for operation on shorter boxes.

A slat hinged at one end thereof and supporting a roller acts to exert a downward force on the stack of boxes in the stacker with the roller being positioned toward the rear of the stack to prevent the portion of the stack engaged by lift screws from rising faster than the leading edge of the stack and thereby tipping the leading edge downward to impede takeoff. Another member also exerts a downward force on the stack primarily at the rear thereof. This member is maintained in a horizontal position by means of parallel linkages in an effort to maintain the folded boxes in the stack in horizontal position.

PATENTEU AUG24 I971 SHEET 3 OF 6 BLANK STACKING, STRAIGHTENING AND DELIVERY MEANS This invention relates to apparatus for producing boxes from corrugated board and more particularly relates to an improved construction for the stacking, straightening and delivery section of the apparatus disclosed in my copending U.S. application Ser. No. 516,421 filed Dec. 27, 1965, now Pat. No. 3,409,148 for an Improved Stacking Device.

Apparatus of the type under consideration includes feed belts which receive blanks issuing from a folding machine as folded tubular boxes and conveys these folded blanks along a generally horizontal feed path to a location where the side edges of the blanks are engaged by lifting screws positioned on opposite sides of the feed path. Shortly thereafter forward movement of the folded blanks is arrested by engagement of the leadingedges of the blanks with a vertically extending barrier positioned forward of the lifting screws. The lifting screws raise the blanks above the feed path to form a bottomfed stack, the top portion of which is engaged periodically by a pusher means operated in timed relationship with the lifting screws. The pusher means moves horizontally from the rear to remove a pile of folded blanks from the top portion of the stack with the pile containing a predetermined number of blanks.

In the apparatus of my aforesaid copending application Ser. No. 516,421 a slapper bar positioned above the feed path en gages the rear edges of the folded blanks while the front edges thereof are in engagement with the barrier. However, there is a space between the feed belts defining the feed path and the slapper to the barrier. The lifting screws are located near the slapper bar to positively impart upward movement at the rear of the folded blanks. However, there is no means positively lifting the forward edges of the folded blanks as they engage the barrier and as a result the lifting of the blanks at the rear end tends to tip the front downward. This condition is further accentuated in that the weight of the folded blanks from above resting upon the lower blanks in the stack so that the leading edge of the bottommost blank in the stack tends to hand on to the conveyor belts and impedes the ability of the next blank being delivered from reaching the barrier.

In order to alleviate this latter condition, the lower vertical surface of the barrier is provided with a downward extension that slopes toward the rear i.e. toward the feed end of the machine. This provides an upward forwardly sloping incline onto which the forward edges of the folded blanks initially rise as their forward progress is arrested by the barrier means. This serves to relieve the downward force acting on the lowermost folded blank in the stack to readily permit entry of succeeding blanks at the bottom of the stack. Entry of preceding blanks is also facilitated by an oscillating roller means that moves between a position below the feed path to one slightly above and engages the lowermost blank in the stack from below at the front thereof.

To permit the apparatus to accommodate different sizes of I folded blanks, the barrier means position is adjustable front and back to a selected position along the feed path. It is very important that the feed belts do not sag in the region where the feed belts intersect the barrier. Thus, a belt-supporting guide roller is connected to the barrier means and is movable therewith. While longer blanks are being handled, it is important that the conveyor belts do not sag rearward ofthe barrier. For this purpose a plurality of roller supports are provided with each being mounted to arms that are pivoted so as to be selectively movable between a lowered position, in which the roller means does not support the belt, to a raised position, in which the belt is supported by the roller means. These arms are so mounted that rearward movement of the barrier causes the guide roller carried thereby to engage the arms for automatic movement thereof to positions therein wherein the roller means becomes disengaged from the belt means.

In order to prevent opening of the glued or taped joints of the-folded blanks, the blanks in the stack rest against one another and a slat resting against the top of the stack exerts a downward force to maintain pressure between adjacent folded blanks. A parallel arm linkage supports the slat in a manner which permits upward movement thereof as stack height increases, yet maintains the slat essentially horizontal to achieve greater accuracy in the count of folded blanks in each pile removed from the top of the stack.

Accuracy is further improved by a weight roller positioned to exert a downward force at the rear of the stack to counteract the positive lifting force of the screws so as to prevent the rear of the stack from rising much faster than the front of the stack which, as previously noted, does not have positive lifting forces exerted thereon. The last recited roller is mounted to a hinged hold down bar or slat at a point forward of the slat rear and where its hinged support is found. This last mentioned slat extends considerably beyond the barrier means to exert a downward force on the pile all during the time when it is moved forward of the barrier means.

Accordingly, a primary object of the instant invention is to provide a novel construction for the stacking, straightening and delivery section of box making machinery.

Another object is to provide a stacking section in which means are provided to reduce forces impeding entry of blanks to the bottom of the stack.

Another object is to provide movable roller means for supporting a conveyor belt in the region where this belt intersects a barrier means which arrests forward movement of folded blanks moving in a horizontal path.

A further object is to provide novel means for selectively positioning belt support rollers.

A further object is to provide a replaceable slat means for exerting holding pressure on joints of folded blanks in a stacking section and to provide means for maintaining said slat generally horizontal.

Yet another object is to provide a roller means mounted to a hinge slat for exerting downward force at the rear of a stack of blanks in which the blanks are being raised at the rear by lift screws.

These, as well as other objects of this invention, will become readily apparent after reading the following description of the accompanying drawings in which:

FIG. 1 is a side elevation of a stacking, straightening and delivery section constructed in accordance with teachings of the instant invention. 7

FIG. 2 is a plan view, looking in the direction of arrows 22 of FIG. 1, showing the portion of the apparatus of FIG. 1 below the belts which drive the delivery means.

FIG. 3 is an enlarged side elevation showing the belt support rollers.

FIG. 4 is a fragmentary perspective showing elements in the region of the front barrier means.

FIG. 5 is an enlarged side elevation of the holddown slat and its parallel linkage mounting.

FIG. 6 is a plan view of the slat of FIG. 5 looking in the direction of arrows 66 of FIG. 5.

FIG. 7 is a side elevation through line 77 of FIG. 8, illustrating means for oscillating the lifting means while blanks are being stacked.

FIG. Sis a plan view of the elements of FIG. 7.

Now referring to the figures. The portions of the box making apparatus incorporating the novel features of the instant invention include conveyor means 11 which receive box blanks in folded tubular form from a folder-gluer or foldertaper (both not shown) positioned to the left of FIG. 1. Conveyor means 11 moves the blanks forward along a generally horizontal feed path delivering them to lift cam operated roller 99 and lift screws l2, 13. The threads of screw means l2, l3 engaged the edges of the folded blanks to impart upward movement to such blanks to form stack 14 which is fed from below. Forward movement of the folded blanks is arrested by front barrier means 15 shown enlarged in FIGS. 3

and 4. Delivery means 16, positioned above stack 14, periodically engages the upper portion of stack 14 to remove a pile 17 of blanks from the top of stack 14 and deliver such pile 17 in a forward direction on to the rollers of conveyor table 18.

Conveyor means 11 comprises opposed continuous belt means 21, 22 which engage folded blanks therebetween delivering them forward (to the right with respect to FIG. 1) to the upper flight of delivery belt means 25 which is supported so that the upper flight at the left thereof provides an upwardly inclined entrance portion 26. The front edges of blanks fed by conveyor means 11 pass lifting screws 12, 13 and are initially supported by belt means 25 which guides the forward edges of the blank to the lower portion of barrier means 15. Lifting screws 12, 13 provide positive upward movement to the blanks of stack 14 in the vicinity of the rear portion of stack 14. At the forward portion of stack 14 the leading edge of a blank newly arrived at the bottom of stack 14 forces blanks thereabove in an upward direction. Holddown sections 28, 29 extending forwardly from frame member 30 provide downward forces acting on stack 14 and its top pile 17 to prevent the glued or taped joints, as the case may be, of the folded tubular boxes from opening prior to setting of the glue. The pair of pushers 32, 32 of delivery means 16 periodically engage the top portion of stack 14 at the rear thereof and move pile 17 in a forward direction or to the right with respect to FIG. 1.

At the end of a run of a given order of boxes, after the last folded box blank entering conveyor means 11 has been fed to the bottom of stack 14, manually operable lifting means 90 is operated to raise the forward end of stack 14 above front gauge 41, at the upper end of barrier means 15, for engagement and removal by pushers 32, 32.

Since details of the chains and sprockets connecting the power source (not shown) to the elements of the apparatus for operation in timed coordinated relationship form no part 'of the instant invention and are within the knowledge of those skilled in the art, descriptions thereof are not contained herein.

The description of the apparatus illustrated in the drawings has, up to this point, been relatively brief. For a more detailed description of the basic elements of the apparatus illustrated, a reference is made to my US. Pat. Nos. 3,203,561, 3,063,577 and 2,963,177, to my aforesaid copending application Ser. No. $16,421, as well as to additional publications and/or patent application referred to in the aforesaid patented documents. Accordingly, the following description will, for the most part, be limited to those elements which per se, or in combination with other elements, constitute the novel features of the instant invention.

Particular attention is directed to FIGS. 3 and 4 for a detailed showing of front barrier which includes upper vertical section 41 spaced from and offset to the rear of lower vertical section 42, the latter being part of transverse member 45. Peripheral portions of continuously rotating rollers 44 provide a transition between vertical sections 41 and 42. Inclined portion 43 of barrier means 15 extends to the rear and downwardly from lower vertical portion 42. The upper flights of the plurality of spaced parallel narrow belt sections 25a, constituting delivery belt 25 extend through notches in transverse member 45 which provides barrier means sections 42 and 43. Member 45 is connected to movable frame member 46 which also carries member 47 having barrier means surface 41 formed thereon.

A plurality of rollers 48 pivotally mounted to the right of member 45 in FIG. 4 support the upper flight of each of the belt sections 25a very close to the point where section 25a intersects barrier means 15. the upper flight of each of the belt sections 25a is also supportable by rollers 51 and 52, rotatably mounted at one end of the arms 53,54 respectively. Pins 55, 56 pivotally mount links or arms 53,54 respectively to stationary bracket 50 at the ends of arms 53,54 remote from rollers 51,52.

With rollers 51,52 in their lowered or inactive positions shown in FIG. 3 they are below the upper flight of delivery belt 25 and do not provide support therefor. This condition prevails when relatively short blanks are being handled. At this time, movable frame supported rollers 48 are adjacent to main support roller 59 at the forward end of delivery belt 25.

With arms 53,54 pivoted clockwise to the phantom positions shown in FIG. 3, rollers 51 and 52 rise to positions supporting the upper flight of delivery belt 25 and remain in this position since pins 57,58 limit clockwise movement of arms 53,54 respectively to a position slightly to the right of center with respect to pivots 55,56. When front barrier means 15 is moved from the position shown in FIG. 1 leftward to the position shown in FIG. 3, as rollers 48 move past rollers 51,52 engagement therebetween moves arms 53,54 in a counterclockwise direction to automatically operate rollers 51,52 to their inactive positions shown in FIG. 3.

The mechanism for oscillating arms 91 of lifting means is seen more particularly in FIGS. 4, 7 and 8 but for the sake of clarity is omitted from FIG. 1. Each of the arms 91 carries freely mounted rollers 92 at one end thereof movable between belt sections 25a. The other end of arm 91 is secured to member which is a square bar 93 turned at both ends to provide journals 95 pivotally mounted on movable frame 46. Member 94, keyed at one end ofjournal 95, is provided with generally horizontally slot 96 which receives arm 97 having cam follower roller 98 pivotally mounted on pin 99 at the bifurcated end 101 of arm 96. Near the other end of arm 97, threaded aperture 102 therein receives thumb screw 103 which extends through a clearance aperture in member 94 and operatively secures arm 97 to member 94 so that the two move in unison with the bearing for journal 95 defining a pivot.

With arm 97 mounted in a position shown in FIGS. 7 and 8 cam follower roller 98 is gravity biased into engagement with cam I04 keyed to shaft 44a which drives front barrier rollers 44. Thus, it is seen that as shaft 44a rotates lifting means rollers 92 are oscillated from their low positions, just below the feed path defined by belt 25 to a position slightly thereabove (indicated by reference numeral 92a in FIG. 7), to engage the bottom of the stack and assist box blanks therein upward along incline 43 of front barrier means 15.

Lifting means 90 is oscillated when very long boxes are being stacked. Preferably the speed of shaft 44a causes lifting means 90 to oscillate through more than one cycle for each blank received. However, the assistance of lifting means 90 is not required during the stacking operation when shorter boxes are being stacked since at this time lift screws 12,13 apply sufficient support in the region of front barrier means 15. Under the latter circumstances arm 97 is rotated so that it extends to the right with respect to FIG. 7 being repositioned in slot 96 and secured by thumb screw 103. Arms 91 are free to rotate counterclockwise by gravity and will assume a stable position with rollers 92 somewhat vertically below the pivot provided by journals 95.

Slapper bar 60, mounted for oscillatory motion parallel to the feed direction of blanks entering stack 14, is positioned at a level which corresponds to a point on barrier 15 which is the top of inclined front barrier section 43. Slapper bar 60 is provided with vertical surfaces 61,62 connected by inclined surface 64. Surfaces 61 and 62 are positioned generally opposite barrier surfaces 41 and 42 with surface 61 being offset in a for ward direction with respect to surface 62. Further, transition surface 64 confronts the peripheral portion of rollers 44 connecting surface 41 and 42. As explained in certain of my aforesaid patents, oscillary motion of slapper bar 60 applies straightening forces to the front and rear edges of the folded tubular boxes as they rise in stack 14 to provide a straightening action for the box panels subsequent to formation of the glue or tape joint but prior to setting of the glue.

As the folded tubular boxes rise in stack 14 they rest against one another to prevent the glued or taped joints, as the case may be, from opening. During the delivery operation downward pressure is maintained on the joints by slat 68 which extends forward from pivot 69 on transversely adjustable frame member 30 to a position over roller conveyor 18. Roller 70 is pivotally mounted at 71 to bracket 72 connected to slat 68 at a position forward of pivot 69 in the region of lift screws 12,13. At the time pushers 32 of delivery means 16 are about to engage the rear of pile 17 for removal thereof from stack 14, roller 70 rests against the top of pile 17 to apply a downward force thereto at the rear thereof which serves to counteract the tendency of the front to sag, this tendency being caused by the thickness of the screw thread which adds to the height of the stack at the rear thereof.

Holddown slat 75 rests against the top ofstack 14 in the region of lift screws 12,13 to assist in maintaining the top of stack 14 substantially horizontal, especially at the time when pushers 32 initially move pile 17 in a forward direction past holdback spring fingers 74 and up inclined surface 76 of member 47.

Slat 75 is located below bar 68 so that while the latter remains in contact with pile 17 during the removaloperation, slat 75 (as shown in FIG. 1) is free to rest against the remaining portion of stack 14 and exert downward pressure at the glue lap region.

As best seen in FIGS. 5 and 6 slat 75 is removably mounted to support 77 pivotally mounted at hinges 78,79 to the lower ends of parallel arms 80,81 respectively. The upper ends of arms 80,81 are pivotally connected at 82,83 respectively, to stationary frame member 30.

The removable connection between slat 75 and support 77 is provided by nut 84 mounted to screw 85 extending upwardly from slat 75 at the rear thereof with nut 84 being spaced from the upper surface of slat 75 by a distance slightly greater than the thickness of member 77. This space is fixed by conelike slat protrusion 86 through which screw 85 extends. Protrusion 86 extends into elongated slot 88 of member 77 having slanted sidewalls corresponding to the slanting surface of protrusion 86. Compression spring 89 extending outwardly through the right open end of housing 190 is secured to member 77 to the right or forward of arm 81 and engages block 191 on the upper surface of slat 75 located at a position sufficiently spaced from screw 85 to provide locking action with support 77, as will be described. Block 191 is held in position by screws 192,192 which extend into upper conical protrusions 193,193 of slat 75 which space block 191 from the upper surface of slat 75 by a distance equal to slightly greater than the thickness of member 77. Protrusions 193 are disposed in elongated slot 194 extending rearward from the forward edge of member 77 In order to dismount slat 75 from member 77, slat 75 is moved rearward to compress spring 89. When nut 84 moves to the rear of member 77, the rear of slat 78 is free to move downward to a position where screw 85 is below slat 75. Thereafter, salt 75 is movable forward until block 191 is forward of member 77.

Slat 75 is removably mounted to member 77 so that the former may be replaced by another slat of suitable length for use with boxes of a particular length. Pivoted parallel arms 80,81 provide a linkage which maintains slat 75 in a generally horizontal position. It is noted that stop 82a prevents gravity from pivoting arms 80,81 counterclockwise to a position as far as the vertical. Thus, when a new run is stared, rising stack 14 will always cause arms 80,81 to pivot counterclockwise with respect to their pivots 82,83.

The provision of inclined surface 43 at the lower end of barrier means 50 facilitates entry of blanks to the bottom of stack 14. That is, the front end of each blank delivered by conveyors 11 and 25 strike inclined surface 43 and naturally tend to move upward as a result of the incline. At the same time, the rear end of the blank is positively lifted by screws 12,13. Thus, the next blank is not required to wedge its way against the resistance offered by the full weight of stack 14 between stack 14 and the upper flight of conveyor belt 25 in order to reach front barrier 15.

Thus, it is seen that the instant invention provides an improved underfeeding stacking, straightening and delivery device by utilizing an inclined surface portion at the bottom of the front barrier means which arrests forward movement of blanks as they enter the stack. Belt friction is reduced and belt life is extended by utilizing a movable roller attached to the front barrier means for support of the stacker conveyor belt at the region where the belt intersects the front barrier means. Additionally, the belt may be supported by other rollers that are mounted to pivoted arms so that this last group of rollers may be selectively operated between active and inactive positions. Additionally, on longer boxes, the leading edges of the boxes are urged upward by the action of vertically oscillating rollers which alternately engage and release the bottom of the stack. Improved holddown means are provided in the form of a slat mounted to a parallel arm linkage and an elongated bar carrying a roller. The slat, roller, and bar all act to exert downward forces on the stack with the force locations being effective to maintain the glue joints closed and to prevent the front end of the stack-from tipping downward and thereby impeding the takeoff operation.

Although there has been described a preferred embodiment of this novel invention, many variations and modification will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. In combination, a machine for operating on box blanks and delivery apparatus adapted for use with said machine; said apparatus comprisinga stacking means and a conveyor means for moving blanks issuing from said machine forward along a generally horizontal feed path to said stacking means; said stacking means constructed to form an underfed stack of those blanks issuing from said machine and including a first means providing a barrier means positioned forward of an entrance to said stacking means; said barrier means extending generally vertically above said feed path and positioned to engage leading edges of blanks moving along said feed path to thereby arrest forward movement of these blanks; means mounting said barrier means for adjustment by forward and rearward movement relative to said feed path, said conveyor means including continuous belt means extending forward of said barrier means; roller means; arm means; said roller means mounted on a rotational axis at one end of said arm means; said arm means being pivotally mounted at the other end thereof to pivot means extending parallel to the rotational axis of said roller means; said arm means being movable about said pivot means for selective operation of said roller means between discrete operative and inoperative positions with said inoperative position being below said operative position; said roller means when in said operative position being positioned between said entrance and said barrier means, and supporting an upper flight portion of said belt means from below; said roller means when in said inoperative position being ineffective to support said belt means.

2. A combination as set forth in claim 1 also including other roller means positioned forward of said roller means; other arm means; said other roller means mounted on a rotational axis at one end of said arm means; said other arm means being pivotally mounted at the other end thereof to other pivot means extending parallel to both of said rotational axes; said other arm means being movable about said other pivot means for selective operation of said other roller means between discrete operative and inoperative positions with the inoperative position for said other roller means being below the operative position therefor; said other roller means when in its said operative position being positioned between said barrier means and said entrance, and supporting another upper flight portion of said belt means from below; said other roller means when in its said inoperative position being ineffective to support said belt means; said arm means and said other arm means being movable independently of each other.

3; In combination, a machine for operating on box blanks and delivery apparatus adapted for use wit said machine; said apparatus comprising a stacking means and a conveyor means for moving blanks issuing from said machine forward along a generally horizontal feed path to said stacking means; said stacking means constructed to form an underfed stack of those blanks issuing from said machine and including a first means providing a barrier means positioned forward of an entrance to said stacking means; said barrier means extending generally vertically above said feed path and positioned to engage leading edges of blanks moving along said feed path to thereby arrest forward movement of these blanks; means mounting said barrier means for adjustment by forward and rearward movement relative to said feed path, said conveyor means including continuous belt means extending forward of said barrier means; roller means; means mounting said roller means for selective operation between an inoperative position below an operative position wherein said roller means supports an upper flight portion of said belt means from below; a roller device in the region of said barrier means and connected thereto for forward and rearward movement therewith; said roller device supporting an upper flight portion of said belt means from below.

4. A combination as set forth in claim 3 in which said roller device is positioned so that upon rearward movement of said barrier means said roller device may engage said roller means and operate the latter to said inoperative position.

5. In combination, a machine for operating on box blanks and delivery apparatus adapted for use with said machine; said apparatus comprising a stacking means and a conveyor means for moving blanks issuing from said machine forward along a generally horizontal feed path to said stacking means; said stacking means constructed to form an underfed stack of those blanks issuing from said machine and including a first means providing a barrier means extending generally vertically above said feed path and positioned to engage leading edges of blanks moving along feed path to thereby arrest forward movement of these blanks; means mounting said barrier means for adjustment by forward and rearward movement relative to said feed path; said conveyor means including continuous belt means extending forward of said barrier means; additional means connected to said barrier means for movement therewith and having a portion positioned rearward of said barrier means and forward of an entrance to said stacking means; means for oscillating said portion between a first position slightly above said feed path and a second position no higher than said feed path whereby said portion lifts blanks supported on said belt means.

6 A combination as set forth in claim 5 in which there is a means for manually operating said portion to a third position to raise blanks from said belt means to a position above said barrier means.

7. A combination as set forth in claim 5 in which said portion is oscillated through a plurality of cycles for each blank delivered to said stacking means. 

1. In combination, a machine for operating on box blanks and delivery apparatus adapted for use with said machine; said apparatus comprising a stacking means and a conveyor means for moving blanks issuing from said machine forward along a generally horizontal feed path to said stacking means; said stacking means constructed to form an underfed stack of those blanks issuing from said machine and including a first means providing a barrier means positioned forward of an entrance to said stacking means; said barrier means extending generally vertically above said feed path and positioned to engage leading edges of blanks moving along said feed path to thereby arrest forward movement of these blanks; means mounting said barrier means for adjustment by forward and rearward movement relative to said feed path, said conveyor means including continuous belt means extending forward of said barrier means; roller means; arm means; said roller means mounted on a rotational axis at one end of said arm means; said arm means being pivotally mounted at the other end thereof to pivot means extending parallel to the rotational axis of said roller means; said arm means being movable about said pivot means for selective operation of said roller means between discrete operative and inoperative positions with said inoperative position being below said operative position; said roller means when in said operative position being positioned between said entrance and said barrier means, and supporting an upper flight portion of said belt means from below; said roller means when in said inoperative position being ineffective to support said belt means.
 2. A combination as set forth in claim 1 also including other roller means positioned forward of said roller means; other arm means; said other roller means mounted on a rotational axis at one end of said arm means; said other arm means being pivotally mounted at the other end thereof to other pivot means extending parallel to both of said rotational axes; said other arm means being movable about said other pivot means for selective operation of said other roller means between discrete operative and inoperative positions with the inoperative position for said other roller means being below the operative position therefor; said other roller means when in its said operative position being positioned between said barrier means and said entrance, and supporting another upper flight portion of said belt means from below; said other roller means when in its said inoperative position being ineffective to support said belt means; said arm means and said other arm means being movable independently of each other.
 3. In combination, a machine for operating on box blanks and delivery apparatus adapted for use wit said machine; said apparatus comprising a stacking means And a conveyor means for moving blanks issuing from said machine forward along a generally horizontal feed path to said stacking means; said stacking means constructed to form an underfed stack of those blanks issuing from said machine and including a first means providing a barrier means positioned forward of an entrance to said stacking means; said barrier means extending generally vertically above said feed path and positioned to engage leading edges of blanks moving along said feed path to thereby arrest forward movement of these blanks; means mounting said barrier means for adjustment by forward and rearward movement relative to said feed path, said conveyor means including continuous belt means extending forward of said barrier means; roller means; means mounting said roller means for selective operation between an inoperative position below an operative position wherein said roller means supports an upper flight portion of said belt means from below; a roller device in the region of said barrier means and connected thereto for forward and rearward movement therewith; said roller device supporting an upper flight portion of said belt means from below.
 4. A combination as set forth in claim 3 in which said roller device is positioned so that upon rearward movement of said barrier means said roller device may engage said roller means and operate the latter to said inoperative position.
 5. In combination, a machine for operating on box blanks and delivery apparatus adapted for use with said machine; said apparatus comprising a stacking means and a conveyor means for moving blanks issuing from said machine forward along a generally horizontal feed path to said stacking means; said stacking means constructed to form an underfed stack of those blanks issuing from said machine and including a first means providing a barrier means extending generally vertically above said feed path and positioned to engage leading edges of blanks moving along feed path to thereby arrest forward movement of these blanks; means mounting said barrier means for adjustment by forward and rearward movement relative to said feed path; said conveyor means including continuous belt means extending forward of said barrier means; additional means connected to said barrier means for movement therewith and having a portion positioned rearward of said barrier means and forward of an entrance to said stacking means; means for oscillating said portion between a first position slightly above said feed path and a second position no higher than said feed path whereby said portion lifts blanks supported on said belt means.
 6. A combination as set forth in claim 5 in which there is a means for manually operating said portion to a third position to raise blanks from said belt means to a position above said barrier means.
 7. A combination as set forth in claim 5 in which said portion is oscillated through a plurality of cycles for each blank delivered to said stacking means. 